Optimal settings for RAID controller - optimized for writes

I’m just about to setup my newly rented DELL R720 12. gen server. It’s running a single Intel Xeon E5-2620 v.2 processor and 64GB ECC ram. I have installed 8 300GB SSDs in it. It has an PERC H710 raid controller (Based on the LSI SAS 2208 dual core ROC). 

Now my database should be optimized for writing. UPDATEs are by far my biggest bottleneck.

Firstly: Should I just put all 8 drives in one single RAID 10 array, or would it be better to have the 6 of them in one RAID 10 array, and then the remaining two in a separate RAID 1 array e.g. for having WAL log dir on it’s own drives?

Secondly: Now what settings should I pay attention to when setting this up, if I wan’t it to have optimal write performance (cache behavior, write back etc.)?